Global warming of 1.5°C (…) in the context of strengthening the global response to the threat of climate change, sustainable development, and

efforts to eradicate poverty

Jean-Pascal van Ypersele(*)

& Philippe Marbaix Université catholique de Louvain (Belgium)

Stakeholders Dialogue, CCPIE/CCIM, Brussels, 25 January 2018

(*) Twitter: @JPvanYpersele, Former IPCC Vice-Chair (2008-2015) Thanks to the Walloon government (funding the Walloon Platform for IPCC) for its support

About the next IPCC Special Report :

Global Mean Temperature in °C relative to 1850 – 1900!Graph: Ed Hawkins (Climate Lab Book) – Data: HadCRUT4 global temperature dataset!

Available on http://openclimatedata.net/climate-spirals/temperature!

Temperature spiral!

!"##$%&'()*($+)%$,)*,&%*$-$,./0'1&$,2'*3&$%/(4($$56'1$#./0'1&$#2'*3&$789:;$

+1.5°C +2°C

~pre-ind

1986-2005

IPCC, AR5, SYR, SPM 8

Regional key risks and potential for risk reduction: Small Islands

!"##$#%

&'#(%)"%%*"+#)+,%+-$+#%

<0/((/)*($5=>$,)*,&*1%'1/)*(;$=>$1&0?&%'1@%&$=>$(&'=.&A&.$

Emissions!(all GHGs)! Sea-level!

~3°C!

~1.5m!

> 3m!

Source: adapted from Schae"er et al., Nature clim. chg. (2012) !

Global average !temperature!

~1.7°C!

< 1m!

#@0@.'1/A&$&0/((/)*($5B@C3&1(;$$'??%)D/0'1&.E$C&1&%0/*&$3.)B'.$F'%0/*3$

Based on IPCC AR5, Synthesis report (2014)!

observed #2015!

IPCC AR5 Synthesis Report

The window for action is rapidly closing 65% of the carbon budget compatible with a 2°C goal is already used NB: this is with a probability greater than 66% to stay below 2°C

Amount Used 1870-2011:

1900 GtCO2

Amount Remaining:

1000 GtCO2

Total Carbon Budget:

2900 GtCO2

AR5 WGI SPM NB: Emissions in 2011: 38 GtCO2/yr

G1'B/./H'1/)*$)+$'10)(?2&%/,$,)*,&*1%'1/)*($%&I@/%&($0)A/*3$'F'E$+%)0$12&$B'(&./*&$J$%&3'%C.&(($)+$12&$0/1/3'1/)*$3)'.$

Based on AR5 WGIII Figure 6.7

>50% chance

s <3°C <3°C <3°C <3°C

likely <2°C

KL!!!$G,&*'%/)($3%)@?($M$4&E$,2'%',1&%/(1/,($

CO2eq Concentrations in

2100 (CO2 eq) !

Category label !(conc. range)!

Subcategories!

Change in CO2eq emissions compared to

2010 (in %)!Temperature

change in 2100 "

- median climate

sensitivity!

Likelihood of staying below specific temperature levels (relative to 1850-1900 = «#pre-industrial#»)!

2050! 2100!

< 430 ! Only a limited number of individual model studies have explored levels below 430 ppm CO2eq!

450 !(430 – 480)! Total range1! -72 to -41! -118 to -78! 1.5-1.7! Likely (66%) to stay below 2°C, #

< 50% chances to stay below 1.5°C!

500 !(480 – 530)!

No overshoot of 530 ppm CO2eq! -52 to -42! -107 to -73! 1.7-1.9! > 50% chances to stay below 2°C!

Overshoot of 530 ppm CO2eq! -55 to -25! -114 to -90! 1.8-2.0! About 50% chances to stay below 2°C!

550 !(530 – 580)!

No overshoot of 580 ppm CO2eq! -47 to -19! -81 to -59! 2.0-2.2!

Likely (66%) to stay below 3°C,!< 50% chances to stay below 2°C!

Overshoot of 580 ppm CO2eq! -16 to 7! -183 to -86! 2.1-2.3!

(580 – 650)! Total range! -38 to 24! -134 to -50! 2.3-2.6!

Based WGIII table SPM.1 (incomplete : higher emissions scenarios not shown)

NOP$GQOM$#'%B)*$C/)D/C&$R$B@C3&1($S$

<3°C!(see AR5 SYR)!

possible?!implications?!

ranges likely to change !at least due to more studies !

(Source: AR5 Synthesis report table 2.2)!

<0/((/)*($/*$(&,1)%(M$B'(&./*&($'*C$R$./4&.E$T$7U#$S$

AR5 SYR figure SPM.14

baselines

mitig.< 2C

2030

2050

2100

2010

UCL # 12

"'%/($'3%&&0&*1$

V! N%1/,.&$7M$!! 5W;$1)$(1%&*312&*$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$,./0'1&$

,2'*3&X$/*$12&$,)*1&D1$)+$(@(1'/*'B.&$C&A&.)?0&*1$'*C$&++)%1($1)$&%'C/,'1&$?)A&%1EX$/*,.@C/*3$BEM$

!!Y).C/*3$12&$/*,%&'(&$/*$12&$3.)B'.$'A&%'3&$1&0?&%'1@%&$1)$F&..$B&.)F$7$U#$'B)A&$?%&=/*C@(1%/'.$.&A&.($'*C$1)$?@%(@&$&++)%1($1)$./0/1$12&$1&0?&%'1@%&$/*,%&'(&$1)$9ZP$U#$'B)A&$?%&=/*C@(1%/'.$.&A&.(X$%&,)3*/H/*3$12'1$12/($F)@.C$(/3*/+/,'*1.E$%&C@,&$12&$%/(4($'*C$/0?',1($)+$,./0'1&$,2'*3&[$$

!! !*,%&'(/*3$12&$'B/./1E$1)$'C'?1$5W;$'*C$+)(1&%$,./0'1&$%&(/./&*,&$'*C$.)F$3%&&*2)@(&$3'($&0/((/)*($C&A&.)?0&*1X$/*$'$0'**&%$12'1$C)&($*)1$12%&'1&*$+))C$?%)C@,1/)*[$$

!!\'4/*3$+/*'*,&$+.)F($,)*(/(1&*1$F/12$'$?'12F'E$1)F'%C($.)F$3%&&*2)@(&$3'($&0/((/)*($'*C$,./0'1&=%&(/./&*1$C&A&.)?0&*1$

Globalwarmingof1.5°C

•  Summaryforpolicymakers(max10pages)

•  Chapters:‣  1.Framingandcontext

‣  2.Mitigationpathwayscompatiblewith1.5°Cinthecontextofsustainabledevelopment

‣  3.Impactsof1.5°Cglobalwarmingonnaturalandhumansystems

‣  4.Strengtheningandimplementingtheglobalresponsetothethreatofclimatechange

‣  5.Sustainabledevelopment,povertyeradicationandreducinginequalities

•  Boxes(integratedcasestudies/regionalandcross-cuttingthemes),

•  FAQs(10pages)

A IPCC special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty

Proposed outline (as adopted in October 2016; report to be finalized in 2018) :

L.)B'.$F'%0/*3$)+$9ZPU#$

V! G@00'%E$+)%$?)./,E$0'4&%($50'D$98$?'3&(;$$

V! #2'?1&%($M$

!! 9Z$]%'0/*3$'*C$,)*1&D1$

!! 7Z$\/1/3'1/)*$?'12F'E($,)0?'1/B.&$F/12$9ZPU#$/*$12&$,)*1&D1$)+$(@(1'/*'B.&$C&A&.)?0&*1$

!! ^Z$!0?',1($)+$9ZPU#$3.)B'.$F'%0/*3$)*$*'1@%'.$'*C$2@0'*$(E(1&0($$

!! _Z$G1%&*312&*/*3$'*C$/0?.&0&*1/*3$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$,./0'1&$,2'*3&$$

!! PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($

V! `)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$

V! ]Na($

A IPCC special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty

Proposed outline (as adopted in October 2016; report to be finalized in 2018):!

7Z$\/1/3'1/)*$?'12F'E($,)0?'1/B.&$F/12$9ZPU#$/*$12&$,)*1&D1$)+$(@(1'/*'B.&$7Z$\/1/3'1/)*$?'12F'E($,)0?'1/B.&$F/12$9ZPU#$/*$12&$,)*1&D1$)+$(@(1'/*'B.&$ Understanding 1.5°C; reference levels, probability,

!transience, overshoot, stabilization (…)!C&A&.)?0&*1$

^Z$!0?',1($)+$9ZPU#$3.)B'.$F'%0/*3$)*$*'1@%'.$'*C$2@0'*$(E(1&0($$

_Z$G1%&*312&*/*3$'*C$/0?.&0&*1/*3$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$,./0'1&$,2'*3&$$

PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($

Understanding 1.5°C; reference levels, probability, transience, overshoot, stabilization (…)transience, overshoot, stabilization (…)

^Z$!0?',1($)+$9ZPU#$3.)B'.$F'%0/*3$)*$*'1@%'.$'*C$2@0'*$(E(1&0($$

_Z$G1%&*312&*/*3$'*C$/0?.&0&*1/*3$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$,./0'1&$,2'*3&$$

Pathways compatible with 1.5°C compared with !2°C (…) Technological, environmental, institutional !and socio-economic opportunities and !!challenges!

_Z$G1%&*312&*/*3$'*C$/0?.&0&*1/*3$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$

PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($

_Z$G1%&*312&*/*3$'*C$/0?.&0&*1/*3$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$_Z$G1%&*312&*/*3$'*C$/0?.&0&*1/*3$12&$3.)B'.$%&(?)*(&$1)$12&$12%&'1$)+$2°C (…) Technological, environmental, institutional

Key global and regional climate changes, !vulnerabilities, impacts, and risks at 1.5°C, taking #!into account adaptation potential (…)!PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($

`)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$

PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($

Key global and regional climate changes, vulnerabilities, impacts, and risks at 1.5°C, taking vulnerabilities, impacts, and risks at 1.5°C, taking PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($PZ$G@(1'/*'B.&$C&A&.)?0&*1X$?)A&%1E$&%'C/,'1/)*$'*C$%&C@,/*3$/*&I@'./1/&($

`)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$

Current and emerging adaptation and mitigation !options, including negative emission !methodologies, & associated opportunities & ! !challenges (…) Case studies!

`)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$`)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$`)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$options, including negative emission methodologies, & associated opportunities & associated opportunities & &methodologies, & associated opportunities & associated opportunities & &`)D&($5/*1&3%'1&C$,'(&$(1@C/&(-%&3/)*'.$'*C$,%)((=,@11/*3$12&0&(;X$

Linkages between achieving SDGs and 1.5°C (…)!

!"#$%&'(")*"+*,-".%-*/#'(('")*-/0/-(*')*1213*%)4*1252*&/(6-7'),*+&"#*78/*'#$-/#/)7%7'")*"+*78/*')7/)4/4*)%7'")%--9*4/7/&#')/4*:")7&'.67'")(*)%7'")%--9

b6]###X$N33%&3'1&$&++&,1$)+$12&$/*1&*C&C$*'1/)*'..E$C&1&%0/*&C$,)*1%/B@1/)*(M$'*$@?C'1&$$211?M--@*+,,,Z/*1-%&()@%,&-C),(-789c-,)?77-&*3-87Z?C+$

;"7%-*,-".%-*/#'(('")(*d)1'.$3.)B'.$&0/((/)*(M$_9Ze$f$7Zg$L1#h7$/*$789PX$_ei$)A&%$9ee8$"&%,&*1'3&$.'*C=@(&$,2'*3&M$^ci$/*$9ec8X$ei$'A&%'3&C$788c=789P$

$G)@%,&M$#j!N#[$Y)@321)*$&1$'.$7897[$L/3./)$&1$'.$789^[$k&$a@l%l$&1$'.$789c[$L.)B'.$#'%B)*$`@C3&1$789:$

d)1'.$3.)B'.$&0/((/)*(M$_9Ze$f$7Zg$L1#h7$/*$789PX$_ei$)A&%$9ee8$"&%,&*1'3&$.'*C=@(&$,2'*3&M$^ci$/*$9ec8X$ei$'A&%'3&C$788c=789P$

Tentativeandpersonalconclusions(TheSR1.5hasnotbeenfinalizedyet!)

1.5°C matters: reducing the warming, even by

tenths of a °C, can make large differences for impacts, as many of these are non-linear, that is they worsen faster with warming than the warming itself.

The probability of extremes (heat waves,

drought, floods, extreme sea level) is significantly lower in a 1.5°C world than in a 2°C world

1.5°C is much safer than 2°C in terms of long-

term sea-level rise associated to ice-sheet processes, particularly for low-lying regions

Tentativeandpersonalconclusions(TheSR1.5hasnotbeenfinalizedyet!)

1.5°C lower impacts will make adaptation less costly than

in 2°C world, even if there is a temporary overshoot above 1.5°C

It is very ambitious to reduce emissions fast enough to

ZERO for a 1.5°C long-term average temperature above pre-industrial objective; a little easier with overshoot above 1.5°C for a short period

The slower radical changes in emission patterns take

place, the more we may need uncertain or risky technologies, such as large use of carbon dioxide removal from the atmosphere (possibly at the expense of bio-energy competition with food production)

Decision making needs the best scientific information

possible – the IPCC SR 1.5 will be essential, but much can be done to raise ambition without waiting for it

StraksbijEPO(februari2018)Voorwoord:JillPeeters

G6.-'N*:8/A*O/*P"/:D*(6$N&'/6&Q*":7".&/*12?3**

Jean-Pascal van Ypersele (vanyp@climate.be)

Pour en savoir plus : !! www.ipcc.ch : GIEC ou IPCC !! www.climate.be/vanyp : beaucoup de mes

dias !! www.plateforme-wallonne-giec.be : Plateforme

wallonne pour le GIEC (e.a., Lettre d’information) !! www.skepticalscience.com : réponses aux semeurs

de doute

!! Sur Twitter: @JPvanYpersele @IPCC_CH